Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2010 / Made available in DSpace on 2012-10-24T22:26:10Z (GMT). No. of bitstreams: 0 / Um dos constituintes do petróleo, o enxofre, é um dos mais prejudiciais poluentes ao meio-ambiente que atualmente existe. Desta forma, políticas ambientais são cada dia mais severas, com o intuito de diminuir a concentração deste componente nos derivados de petróleo, incorrendo assim em custos adicionais para a indústria do petróleo, objetivando a diminuição de compostos sulfurados em seus produtos. Estes compostos são geralmente retirados das correntes de destilados por processo catalítico de hidrogenação, sob condições de elevadas temperaturas e pressões, chamado de hidrotratamento (HDT), sendo assim, um processo de elevado custo operacional. A adsorção se mostra como um excelente processo de pré ou póstratamento das correntes de HDT, por operar em baixas pressões e temperaturas, diminuindo assim as condições severas de processamento e da mesma forma os custos de capital e operacional. A literatura já traz trabalhos relacionados à dessulfurização por adsorção de destilados leves que originam combustíveis tais como gasolina, óleo diesel e combustível de aviação. Porém, os destilados de petróleo mais pesados que originam óleos lubrificantes, ainda não foram abordados na literatura com relação à aplicação do método adsortivo para dessulfurização. Os lubrificantes possuem um valor agregado cerca de três vezes maior que os combustíveis convencionais, possuindo assim um grande atrativo econômico. Desta forma, no presente de trabalho foi estudada a adsorção de compostos orgânicos sulfurados em destilados pesados naftênicos industriais e sintéticos, utilizando carvão ativado como adsorvente. O carvão ativado foi escolhido devido à sua grande capacidade de adsorção a uma grande gama de compostos organo-sulfurados, reportadas em trabalhos científicos para combustíveis convencionais. O estudo adsortivo consistiu no levantamento de isotermas de equilíbrio, tanto para frações naftênicas de petróleo, como para compostos sintéticos, objetivando a determinação da capacidade e seletividade adsortiva do carvão; da mesma forma, houve o estudo de curvas cinéticas de adsorção, visando à determinação do comportamento difusivo do sistema em estudo. As influências da temperatura, da massa molecular, da presença de inibidores (água, fenol, naftaleno e carbazol) e da concentração inicial de compostos sulfurados usualmente presentes em destilados pesados foram determinadas em processo de batelada. Foram desenvolvidos modelos para representar o processo adsortivo em estudo e um algoritmo para a predição do comportamento cinético do sistema via simulação numérica. Os resultados encontrados mostraram que, de uma forma geral, o aumento da massa molecular das moléculas sulfuradas presentes nos destilados naftênicos, assim como, a presença de moléculas de outras classes orgânicas, atuando como inibidores, desfavoreceram o fenômeno adsortivo dos compostos sulfurados sobre o carvão ativado. Já o aumento da temperatura favoreceu a adsorção dos compostos sulfurados dos destilados de petróleo, devido a uma possível resistência difusional de acesso aos sítios ativos do carvão, a qual diminuiu com o aumento da temperatura, ou seja, o aumento da energia interna das moléculas. / Sulfur is a component of the oil, which is one of the most dangerous pollutants that exist at the environmental. Therefore politics are harder to decrease the sulfur concentration in refined oils that increase the oil industry costs. This component is normally extracted by hydrogen catalytic processes of distilled streams, at high pressures and temperatures, called hydrotreatment (HDT). The adsorption is presented as an excellent treatment of the inner and outers HDT streams, decreasing their severity, capital and operation costs. The literature shows works which are related with distilled oils desulfurization by adsorption, that origin fuels like gasoline, óleo diesel and aviation fuel. However, the heavier distilled oils which originate lubrificating base oil were not studied yet about the use of adsorption methods to desulfurization. These lubrificating base oils have monetary values about two or three times higher than the conventional fossil fuels, having a great economic attractive. Therefore, the sulfur species adsorption in commercial and synthetic naphthenic heavy distilled oils, using activated carbon as adsorbent was studied in this work. The activated carbon was chosen due to its high capacities adsorption to great variety of sulfur compounds, reported in scientific works to conventional fossil fuels.
The adsorption study was based on thermodynamic adsorption on synthetic and real distillates, getting adsorbent capacities and selectivities, and on kinetics adsorption determining diffusivity behavior of the systems. The temperature, molecular size, inhibitors presence (water, phenol, naphtalene and carbazole) and initial concentration influences of the common sulfur species encountered in heavy distillates were determine in batch experiments. Models were developed to represent de experimental data and a numeric algorithm was made to predict the kinetic behavior of the system. In general, the results showed that the sulfur molecular size increasing and the presence of molecules with other molecular composition, acting as inhibitors, decrease the adsorption of sulfur compounds on activated carbon. However, the temperature increasing gives a better sulfur compounds adsorption to petroleum distillates, due to a possible diffusional resistance of activated sites access, which is decreased to higher temperatures, due to molecular internal energy increasing.Sulfur is a component of the oil, which is one of the most dangerous pollutants that exist at the environmental. Therefore politics are harder to decrease the sulfur concentration in refined oils that increase the oil industry costs. This component is normally extracted by hydrogen catalytic processes of distilled streams, at high pressures and temperatures, called hydrotreatment (HDT). The adsorption is presented as an excellent treatment of the inner and outers HDT streams, decreasing their severity, capital and operation costs. The literature shows works which are related with distilled oils desulfurization by adsorption, that origin fuels like gasoline, óleo diesel and aviation fuel. However, the heavier distilled oils which originate lubrificating base oil were not studied yet about the use of adsorption methods to desulfurization. These lubrificating base oils have monetary values about two or three times higher than the conventional fossil fuels, having a great economic attractive. Therefore, the sulfur species adsorption in commercial and synthetic naphthenic heavy distilled oils, using activated carbon as adsorbent was studied in this work. The activated carbon was chosen due to its high capacities adsorption to great variety of sulfur compounds, reported in scientific works to conventional fossil fuels.
The adsorption study was based on thermodynamic adsorption on synthetic and real distillates, getting adsorbent capacities and selectivities, and on kinetics adsorption determining diffusivity behavior of the systems. The temperature, molecular size, inhibitors presence (water, phenol, naphtalene and carbazole) and initial concentration influences of the common sulfur species encountered in heavy distillates were determine in batch experiments. Models were developed to represent de experimental data and a numeric algorithm was made to predict the kinetic behavior of the system. In general, the results showed that the sulfur molecular size increasing and the presence of molecules with other molecular composition, acting as inhibitors, decrease the adsorption of sulfur compounds on activated carbon. However, the temperature increasing gives a better sulfur compounds adsorption to petroleum distillates, due to a possible diffusional resistance of activated sites access, which is decreased to higher temperatures, due to molecular internal energy increasing.Sulfur is a component of the oil, which is one of the most dangerous pollutants that exist at the environmental. Therefore politics are harder to decrease the sulfur concentration in refined oils that increase the oil industry costs. This component is normally extracted by hydrogen catalytic processes of distilled streams, at high pressures and temperatures, called hydrotreatment (HDT). The adsorption is presented as an excellent treatment of the inner and outers HDT streams, decreasing their severity, capital and operation costs. The literature shows works which are related with distilled oils desulfurization by adsorption, that origin fuels like gasoline, óleo diesel and aviation fuel. However, the heavier distilled oils which originate lubrificating base oil were not studied yet about the use of adsorption methods to desulfurization. These lubrificating base oils have monetary values about two or three times higher than the conventional fossil fuels, having a great economic attractive. Therefore, the sulfur species adsorption in commercial and synthetic naphthenic heavy distilled oils, using activated carbon as adsorbent was studied in this work. The activated carbon was chosen due to its high capacities adsorption to great variety of sulfur compounds, reported in scientific works to conventional fossil fuels.
The adsorption study was based on thermodynamic adsorption on synthetic and real distillates, getting adsorbent capacities and selectivities, and on kinetics adsorption determining diffusivity behavior of the systems. The temperature, molecular size, inhibitors presence (water, phenol, naphtalene and carbazole) and initial concentration influences of the common sulfur species encountered in heavy distillates were determine in batch experiments. Models were developed to represent de experimental data and a numeric algorithm was made to predict the kinetic behavior of the system. In general, the results showed that the sulfur molecular size increasing and the presence of molecules with other molecular composition, acting as inhibitors, decrease the adsorption of sulfur compounds on activated carbon. However, the temperature increasing gives a better sulfur compounds adsorption to petroleum distillates, due to a possible diffusional resistance of activated sites access, which is decreased to higher temperatures, due to molecular internal energy increasing.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufsc.br:123456789/93444 |
| Date | 24 October 2012 |
| Creators | Moreira, Alexandre Marques |
| Contributors | Universidade Federal de Santa Catarina, Souza, Antonio Augusto Ulson de, Souza, Selene Maria de Arruda Guelli Ulson de |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | 171 p.| il., grafs., tabs. |
| Source | reponame:Repositório Institucional da UFSC, instname:Universidade Federal de Santa Catarina, instacron:UFSC |
| Rights | info:eu-repo/semantics/openAccess |
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